


const String html_str="<!DOCTYPE html>"+
    "    <html lang=\"en\">"+
"<head>"+
"<meta charset=\"UTF-8\">"+
"<meta http-equiv=\"X-UA-Compatible\" content=\"IE=edge\">"+
"<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">"+
"<title>Document</title>"+
"</head>"+
"<body>"+
"<div style=\"width: 200px;height: 300px;background-color: aqua;\">123</div>"+
"</body>"+
"<script>"+
"window.onload=function(){"+
"  document.getElementsByTagName(\"div\")[0].onclick=function(){"+
"    Print.postMessage('Hello');"+
"  }"+
"}"+
"</script>"+
"</html>";